In order to migrate your POP3 email account to Crucial, you will need to take an email backup and create the new Crucial hosted email account with this backup.
Migrate via Backup This guide demonstrates how to do this with Outlook 2013, however the process is similar for Outlook 2010.
Open your Outlook program
Click on Open & Export
Then select Import/Export
Select Export to a file and click on Next
Choose Outlook Data File (.pst) and select Next
This will then present you with a menu where you can select the folders you wish to export to the data file, once this has been selected hit Next
You will then be prompted with the following selection, choose where you would like to save the exported data file and any options you may want to include. Then select Finish
Migrate via Restore
Then select Add Account
Select Manual Setup or additional server types
Then select POP or IMAP and click Next
You will then be presented with the following menu, make sure that you 'Deliver new messages to' the Existing Outlook Data File (this is the backup you just created) browse to the location where it was saved
Once this has been completed, fill out the rest of the account information and select Next
Mac Mail This guide shows how to Export a Mailbox using OSX Yosemite (10.10)
Migrate via Backup
Select one or more mailboxes, then choose Mailbox > Export Mailbox
Then select a folder (or create a new folder) this will export the mailbox. This will be exported as a .mbox file
Migrate via Restore
Select File then click Import Mailboxes
Select Files in mbox format and click continue
This will then prompt you for a location of the previously exported mbox files
Once this has been done, select Choose. This will then import the data.
Tip: POP3 is an email protocol that stores your emails on a local device (such as your computer or phone). This means that the emails are downloaded off the server, and in most default configurations will be removed off the server in 14 days.